UNIVERSITY  OF  CALIFORNIA  agricultural  Experiment  Station 

COLLEGE  OF  AGRICULTURE  THOMAS  FORSYTH   HUNT.  DIRECTOR 

BERKELEY,  CALIFORNIA 


CIRCULAR  No.  87 


ALFALFA. 

Warren  T.  Clarke. 
This  wonderful  forage  plant  was  introduced  to  this  State  some 
time  between  the  years  1851  and  1854,  and  has  not  only  become,  in 
the  time  that  has  elapsed  since  its  introduction,  the  standard  forage 
plant  of  California,  but  it  has  also  become  known  and  appreciated 
far  beyond  the  boundaries  of  the  State.  The  annual  value  of  the 
crop  in  California  approximates  some  thirty-five  millions  of  dollars 
now  and  the  acreage  devoted  to  its  culture  is  constantly  being  in- 
creased. In  view  of  these  facts  and  recognizing  the  fact  that  concise 
information  in  the  matter  is  demanded  by  both  old  and  new  planters 
the  following  summary  of  practice  is  presented. 

SOTL   REQUIREMENTS. 

Alfalfa  is  a  deep  feeding  plant,  sending  its  long  tap  root  far  down 
into  the  soil  for  nutriment.  This  deep  feeding  character  of  the  plant 
should  be  noted  and  so  far  as  possible  the  fact  should  be  taken  into 
consideration  by  the  intending  planter.  A  deep,  well-drained,  moder- 
ately heavy  loam  with  no  hardpan  strata  between  the  surface  soil 
and  the  water  bearing  strata  is  to  be  preferred.  Our  best  alfalfa 
fields  are  on  such  soils  as  these  where  surface  water  is  to  be  found 
at  from  twelve  to  twenty  feet  down.  This  optimum  of  soil  conditions 
should  be  sought  by  the  intending  planter ;  yet  because  of  the  adapta- 
bility of  the  plant,  he  may  allow  himself  considerable  latitude  in  the 
choice.  Satisfactory  alfalfa  plantations  are  to  be  found  on  our  very 
light  sandy  loams  and  on  our  very  heavy  adobe  lands. 

Noting  the  deep  rooting  habit  of  this  plant,  those  soils  where  free 
water  is  found  close  to  the  surface  should  be  avoided.  Under  these 
conditions  the  tap  root  is  likely  to  decay  and  the  plant  will  suffer  if 
it  does  not  succumb.  Good  drainage  of  the  soil  is  an  essential  for 
success  with  this  crop. 

Most  of  our  California  soils  are  well  supplied  with  the  mineral 
plant  food  necessary  for  success  with  alfalfa,  but,  in  many  of  these 
soils,  there  is  a  deficiency  of  decomposing  organic  matter,  of  humus. 
In  this  latter  case  it  may  be  necessary  to  supply  the  lack  by  growing 
a  winter  green  manure  crop  on  the  land  and  plowing  it  in,  in  the 
spring,  before  seeding  to  alfalfa.  The  character  of  the  green  manure 
crop  will  vary  with  the  local  climatic  conditions  though  "the  most 
favorable  immediate  results  can  probably  be  secured  by  the  use  of 
rye.  This  should  be  seeded  at  the  rate  of  80  pounds  per  acre." 
(U.  of  C.  Exp.  Sta.  Bull.  211,  p.  271.) 

(1) 


—  2  — 

CLIMATIC  REQUIREMENTS. 

The  first  recorded  seed  of  alfalfa  brought  into  California  came  no 
doubt  from  Chili.  Planted,  as  it  was,  in  the  great  inland  valleys  of 
the  State,  its  production  here  was  begun  under  climatic  conditions 
very  similar  to  those  from  whence  came  these  first  seed  importations. 
Soon,  however,  its  adaptability  to  conditions  very  different  to  those 
found  in  the  great  valleys  was  proved  and  it  is  now  a  staple  crop 
from  the  most  northern  counties  of  the  State  to  the  most  southern. 
Alfalfa,  however,  seems  to  do  best  away  from  the  immediate  influence 
of  the  coast  climatic  conditions.  For  its  best  growth  and  production 
a  long,  hot  growing  season  is  desirable  and  the  longer  this  growing 
season  is,  if  other  conditions  are  favorable,  the  greater  will  be  the 
number  of  crops  cut  each  year  and  the  greater  will  be  the  yield.  This 
optimum  of  climatic  conditions  then  should  be  sought  by  the  intend- 
ing planter.  However,  wonderfully  satisfactory  plantations  of  alfalfa 
are  to  be  found  in  regions  of  this  State  where  the  growing  season  is 
short.  So  we  are  justified  in  saying  that  the  adaptability  of  the  plant 
allows  of  its  use  under  a  great  variety  of  climatic  conditions. 

WATER  REQUIREMENTS. 

Under  our  California  conditions  of  climate  and  soil  the  intending 
planter  of  alfalfa  should  be  able  to  command  irrigation  water  for 
his  fields,  either  by  gravity  ditch  or  through  wells  and  pumping 
systems.  In  general,  this  command  of  water  may  be  considered  as 
an  essential  for  success.  It  is  true  that  many  alfalfa  fields  are  to  be 
found  in  this  State  where  no  facilities  for  irrigation  exist  and  yet 
good  crops  are  harvested  for  terms  of  years ;  still  the  success  of  these 
occasional  fields  is  not  so  great  as  it  would  be  were  water  available 
when  needed.  Both  pocket  gophers  and  squirrels  are  a  pest  in  alfalfa 
fields  and  the  only  fully  effective  way  to  destroy  them  is  by  drown- 
ing. If  the  general  soil  conditions  do  not  seem  to  demand  the  use 
of  irrigation  water  for  the  success  of  the  crop  yet  the  possibility  of 
drowning  out  these  pests  must  be  considered. 

As  to  the  amount  of  water,  the  intending  planter  should  be  pre- 
pared to  use  for  irrigation  purposes,  the  figures  will  vary  with  the 
character  of  the  soil  and  with  the  depth  of  soil  to  the  water  table. 
In  the  Sacramento  Valley  with  a  rainfall  of  from  18  to  20  inches  a 
year,  from  3  to  18-acre  inches  of  irrigation  water  are  used.  This 
great  variation  at  least  emphasizes  the  fact  that  the  amount  of  irri- 
gation water  will  depend  on  the  individual  need  of  different  fields 
at  different  times  and  no  set  rule  as  to  amount  to  be  used  can  be 
enunciated.  The  needs  of  the  field  must  be  determined  by  the 
irrigator. 


—  3  - 


PREPARATION  OF  THE  LAND. 


Much  of  the  land  that  is  being  put  into  alfalfa  in  this  State  has 
been  used  previously  either  for  pasture  purposes  or  for  grain  grow- 
ing. In  either  case,  but  more  especially  in  the  latter,  the  physical 
condition  of  the  soil  is  bad.  Almost  invariably  we  find  in  these 
lands  at  a  depth  of  a  few  inches  what  is  commonly  known  asa"  plow 
sole"  or  "cultivation  hard  pan."  This  is  in  no  wise  to  be  considered 
as  a  true  hardpan,  but  is,  more  correctly  speaking,  a  concentration 
at  the  ordinary  cultivation  depth  of  the  finer  particles  from  the  upper 
strata  of  the  soil.  This  "plow  sole"  must  be  broken  up  to  obtain 
satisfactory  results  from  the  land  in  growing  alfalfa.  The  first  move 
then,  in  the  proper  preparation  of  land  for  alfalfa,  is  to  plow  it  deeply 
so  as  to  fully  break  up  the  "plow  sole."  This  deep  plowing  should 
be  done  before  any  leveling  is  done.  In  many  cases  that  we  have 
studied  the  plowing  has  been  done  after  leveling,  and,  as  a  conse- 
quence, in  the  low  places,  filled  in  with  moved  earth,  the  plow  sole 
has  not  been  broken  up.  The  result  has  been  that  in  a  short  time— 
a  year  or  tAvo— the  field  presented  a  spotted  appearance  and  the 
alfalfa  failed  to  produce  as  it  should  in  the  places  where  breaking 
had  not  been  done. 

The  land  should  be  well  leveled  so  that  it  can  be  irrigated  in  the 
most  economical  way.  To  do  this  the  services  of  a  surveyor  should 
be  called  in  and  levels  determined.  If  the  square  check  system  of 
irrigation  is  to  be  used,  the  checks  should  be  of  such  a  size  as  will 
permit  of  the  high  point  being  covered  with  water  to  a  depth  of  three 
inches  at  least  with  a  levee  system  of  not  more  than  twelve  inches  in 
height  at  its  highest  point.  The  levees  should  be  made  both  broad 
and  low,  not  more  than  twelve  inches  high  at  the  most,  as  before 
stated,  so  that  when  the  field  is  producing,  the  various  implements, 
mowing  machines,  rakes,  wagons,  and  so  on  may  be  used  over  the 
field  as  a  whole  without  reference  to  the  levees.  The  slope  of  the 
land  may  be  such  that  contour  line  levees  may  have  to  be  used.  If 
this  is  the  case,  the  same  general  principle  of  low  leVees  holds.  In 
certain  cases  it  may  be  desirable  to  use  the  strip  system  of  levee 
placing.  This  system  can  be  used  to  advantage  where  the  soil  is 
moderately  heavy  and  where  the  land  slope  is  not  too  abrupt. 

While  deep  plowing  is  essential  in  the  proper  preparation  of  land 
for  alfalfa  planting,  it  should  be  remembered  that  the  alfalfa  seed 
demands  a  firm,  compact  seed  bed  for  its  best  success.  Therefore, 
after  the  land  has  been  deeply  plowed,  leveled  and  scraped  and  then 
replowed,  it  should  be  gone  over  carefully  with  some  sort  of  com- 
pacter.  An  ordinary  roller  followed  by  a  light  harrow  may  be  used. 
The  disk  cultivator  with  the  bar  set  straight  has  been  successfully 
used  for  compacting.  Indeed,  any  implement  that  will  compact  the 
soil  somewhat  and  still  leave  the  surface  fairly  loose  may  be  used. 


SEEDING. 

The  first  question  that  will  arise  in  the  mind  of  the  intending 
planter,  when  it  comes  to  a  choice  of  seed/  probably  will  be  as  to  the 
variety  of  alfalfa  to  plant.  Studies  of  this  question  indicate  that 
for  the  general  conditions  found  in  California,  the  Chilian  alfalfa, 
the  first  to  be  introduced  to  the  State,  is  the  most  satisfactory.  For 
the  ordinary  plantings  then,  in  our  great  valleys,  either  north  or 
south,  good,  clean,  vigorous  seed  of  this  variety,  should  be  used.  The 
source  of  this  seed,  that  is,  the  locality  ivhere  grown,  should  be  known 
by  the  planter  so  that  its  desirability  may  be  in  part  at  least  predi- 
cated. Four  ounce  samples  of  the  seed  may  be  sent  to  the  Experi- 
ment Station,  Berkeley,  California,  for  purity  and  germination  test. 
This  service  is  performed  gratis  and  the  intending  planter  should 
certainly  take  advantage  of  it, so  that  he  may  be  sure  he  is  using 
strong  seed  free  from  dodder  and  other  noxious  weed  seeds. 

If  the  conditions  of  moisture,  climate  and  soil  are  not  wholly  satis- 
factory, the  intending  planter  should  use  the  Turkestan  variety  of 
alfalfa.  This  variety  will  crop  on  less  water  than  will  the  Chilian 
and  will  make  a  better  growth  in  cold  weather  than  will  this  last. 
The  Turkestan  alfalfa  does  not,  here  in  California,  make  as  fine  and 
clean  feeding  a  hay  as  does  the  Chilian.  A  third  variety  of  alfalfa, 
known  as  Arabian,  is  desirable  for  certain  special  purposes.  It  is 
known  as  a  five  year  perennial,  while  those  previously  here  men- 
tioned are  known  as  twenty-five  year  perennials.  The  Arabian 
alfalfa  is  especially  good  for  heavy  soils,  makes  a  good  winter  growth, 
and  the  product  is  fine  in  character.  It  is  especially  to  be  recom- 
mended for  orchard  interplanting,  as  it  begins  to  fail  in  the  fifth  or 
sixth  year  of  its  growth  and  can  be  easily  plowed  out  of  the  orchard 
when  the  trees  are  making  strong  demands  on  the  soil.  Many  other 
varieties  of  alfalfa  have  been  tested  in  California,  but  so  far  the 
choice  seems  to  lie  between  the  three  varieties  named. 

The  amount  of  seed  used  per  acre  varies  very  materially  with  different 
planters,  but  careful  studies  of  the  question  indicate  that  if  a  clean, 
vigorous  seed  is  used,  from  twelve  and  a  half  (12-J-)  to  fifteen  (15) 
pounds  per  acre  is  ample.  Using  more  of  such  seed  would  mean 
waste.  This  seed  should,  for  best  results,  be  drilled  into  the  well 
prepared  land  and  no  nurse  crop  used.  Some  planters  use  a  nurse 
crop  of  some  cereal,  but  the  practice  does  more  harm  to  the  young 
alfalfa  plants  in  robbing  them  of  moisture  than  it  does  good  in  a 
fancied  protection. 

The  time  of  planting  will  depend  altogether  upon  the  frost  con- 
ditions in  the  locality  where  the  planting  is  to  be  made.  The  fact 
should  be  noted  that  the  alfalfa  plant,  when  in  the  seed  leaf  stage, 
is  easily  killed  by  frost.  If,  then,  frosts  are  likely  to  occur  in  the 
region  where  the  plantings  are  being  made  in  the  fall,  seeding  should 
be  postponed  until  all  danger  of  cold  is  over  in  the  spring.  After 
the  plant  has  passed  the  seed  leaf  stage  it  is  much  more  resistant 
to  frost. 


—  5  — 

INOCULATION. 

It  is  a  well  recognized  fact  that  for  full  success  in  growing  alfalfa 
the  plants  must  be  supplied  with  nitrogen  gathering  bacteria.  These 
minute  organisms,  so  essential  to  the  proper  growth  of  this  plant, 
are  usually  present  in  our  California  soils,  but  as  a  general  thing 
artificial  inoculation  should  be  practiced.  Where  new  plantings  are 
to  be  made,  especially  if  at  a  distance  from  other  plantings,  it  is  the 
part  of  wisdom  to  insure  the  presence  of  bacteria  by  some  inoculating 
process.  There  are  to  be  obtained  on  the  market  pure  cultures  of 
bacteria  for  the  purpose  in  question,  and  under  some  conditions  it 
may  be  desirable  to  use  these  cultures.  Generally,  however,  a  perfect 
inoculation  can  be  obtained  by  broadcasting  one  or  two  hundred 
pounds  of  soil  from  some  well  growing  alfalfa  field  over  each  acre 
of  the  new  field.  This  inoculating  soil  should  be  well  harrowed  into 
the  land  before  seeding  is  done.  The  process  is  not  difficult  and 
requires  no  technical  skill. 

Inoculation  can  also  be  most  satisfactorily  accomplished  by  what 
is  known  as  the  "soil  suspension"  method.  A  quantity  of  soil  is 
taken  from  some  alfalfa  field  that  is  growing  well  and  upon  the  roots 
of  the  plants  of  which  the  nodules,  indicating  the  presence  of  the 
desired  bacteria,  can  be  found.  To  the  volume  of  soil  used  two  or 
three  times  its  volume  of  water  is  added.  This  is  stirred  vigorously 
several  times  a  day  for  two  days,  and  then  the  earth  is  allowed  to 
settle.  The  alfalfa  seed  is  then  dipped  in'  the  water  which"  now 
carries  the  bacteria.  The  seed  then  is  dried  in  the  shade  enough  so 
that  it  separates  readily.  Planting  should  then  follow  immediately. 
The  method  has  the  advantage  of  being  cheap,  easy  and  effective. 
The  planter  of  alfalfa  should  certainly  insure  the  presence  of  these 
necessary  bacteria. 

IRRIGATION  AND  TIME  OF  CUTTING. 

It  has  been  previously  pointed  out  that  no  definite  rule  as  to  the 
amount  of  water  to  be  used  in  growing  alfalfa  can  be  laid  down. 
In  general,  however,  experience  indicates  that  frequent  shallow  irri- 
gations are  to  be  preferred  to  occasional  heavy  fioodings.  In  the 
writer's  experience  and  observation  an  irrigation  of  about  three  acre 
inches  ten  days  before  cutting  the  alfalfa  brings  the  best  result  on 
most  soils. 

Irrigating  at  this  time  before  cutting  has  a  tendency  to  overcome 
leaf  shedding,  and  it  should  be  remembered  that  the  best  part  of  the 
food  value  of  alfalfa  is  in  the  leafage.  Alfalfa  should  not  be  allowed 
to  become  too  mature  before  cutting  as  when  this  occurs  there  is  sure 
to  be  considerable  leaf  dropping  and  food  loss.  There  are  two  good 
rules  to  follow  in  determining  time  to  cut.  The  first  of  these  rules 
is  to  cut  when  an  occasional  blossom  is  to  be  seen  in  the  field.     This 


—  6  — 

is  a  fairly  good  rule,  but  the  second,  to  cut  when  new  growth  appears 
at  the  crown  of  the  plant,  is  perhaps  more  reliable. 

Finally,  the  alfalfa  planter  should  remember  that  he  is  dealing 
with  a  growth  of  high  food  value,  capable  of  being  used  as  a  ration 
for  all  farm  animals,  and  a  plant  that  will  continue  to  produce  well 
through  a  generation,  and  perhaps  longer,  and  he  should,  therefore, 
spare  no  pains  in  getting  the  best  results  from  his  plantings.  Proper 
care  at  all  points  will  accomplish  this. 


